Field of the Invention
The present invention pertains to devices and methods for bonding angioplasty balloons on catheters. More particularly, the present invention pertains to a segmental crimping device that comprises a radio frequency (RF) heating element in each of its segments. By crimping the cuff of the angioplasty balloon radially inward against a catheter and thereafter activating the heating elements, the cuff can be thermally bonded to the catheter.
General Background
There are several common techniques used to secure angioplasty balloon cuffs to catheters. One technique involves the use of hot jaw clamps and PTFE or FEP heat shrink material. Another similar method uses hot air and PTFE or FEP heat shrink material. Still another method involves the use of lasers and PTFE or FEP heat shrink material. All of these methods utilize heat shrink material placed over the balloon cuff to provide the hoop tension necessary to form an acceptable and annularly contiguous annular thermal bond between the balloon cuff and catheter. As can be appreciated, the heat shrink material must also conduct the heat necessary to melt the balloon cuff. When using hot jaws, the heat begins to transfer less effectively as the heat shrink pulls away from the jaws. This is problematic in that it causes variation in bond strength as a result. In the case of hot air, it is inherently difficult to maintain thermal control and it is often difficult to properly and consistently aim the hot air flow. Moreover, changes in ambient conditions can result in changes in bond properties. In the case of laser bonding, the heat is generated when the laser is absorbed by the catheter. The catheter then transfers the heat radially outward into the balloon cuff. That is problematic in that the absorption rate is impacted by the pigment, surface texture, and/or reflectivity of the catheter, which may vary from one catheter to the next. Moreover, relying on heat shrink material to generate the hoop tension necessary to form an acceptable bond is inherently problematic given that the properties of the heat shrink material often varies from batch to batch and the hoop tension generated is impacted by temperature exposure.
In view of the foregoing, prior art techniques of bonding angioplasty balloon cuffs to catheters have drawbacks.